Avicenna Journal of Clinical Microbiology and Infection
Volume:10 Issue: 1, Mar 2023

Extended-spectrum β-lactamase (ESβL) or metallo-β-lactamase (MβL) production by gram-negative bacteria in immunocompromised patients poses a serious therapeutic challenge for infection control and is associated with infections with a higher morbidity/mortality, especially in developing countries. This study aimed to phenotypically evaluate the production of ESβL as well as MβL in 75 gram-negative bacterial isolates from clinical samples of the human immunodeficiency virus (HIV) positive individuals.

Bacterial identification was by chromogenic media, analytical profile index 20 E, and 20 NE kits, and ESβL production was tested by double-disc synergy test (DDST) and combination disc method, while MβL production was screened with imipenem ethylene diamine tetra-acetic acid (EDTA) combined disc and EDTA-disc potentiation with ceftazidime.

Altogether, 57 isolates (76.0%) produced ESβL either with DDST (6), combination disc method (49), or both (2). DDST detected the ESβL enzyme in 10.7% of the tested isolates which were all Pseudomonas aeruginosa. None of the bacterial isolates revealed MβL production with the imipenem/imipenem-EDTA method, whereas 26.7% of tested isolates produced MβL with EDTA-disc potentiation using ceftazidime out of which 65.0% were P. aeruginosa. Moreover, ESβL/MβL co-production was evident in 22.7% of the tested bacterial isolates with P. aeruginosa constituting 64.7%.

ESβL and MβL co-production among the studied isolates indicates a heightened resistance to β-lactam antibiotics, suggesting grave health consequences, especially in immunocompromised individuals with already limiting therapeutic options in the region. The study revealed higher ESβL production compared to MβL production in isolates, with the predominating producing specie being P. aeruginosa, and higher ESβL and MβL detection by the combination disc method and EDTA-disc potentiation using ceftazidime, respectively.

Brucellosis is recognized as one of the most prevalent diseases among humans and animals. This study investigated and followed up brucellosis in seropositive participants in the Famenin (Hamadan province, Iran) cohort of brucellosis and their families by culture and serology methods.

Blood samples were taken from 66 subjects, including 18 subjects in the Famenin brucellosis cohort study with antibody titers≥1:180 and 36 subjects from their families and 12 subjects in the Famenin brucellosis cohort study with antibody titers<1:80. In the serological method, standard tube agglutination test (STAT positive with≥1:80) and 2-mercaptoethanol (2-ME) test (positive with≥1:40) were performed using the patient serum. Finally, 8 cc of the blood of all subjects was used for culture in the BACTEC culture medium.

Of the 66 serum samples, 20 (30.3%) samples, including 5, 4, and 10 samples at 1:20, 1:40, and 1:80 dilution, respectively, and 1 sample at 1:160 dilution were positive by the STAT, of which 13 (65%) samples belonged to patients’ family members. Using the 2-ME test, 10 (15.2%) serum samples were positive, of which 5 (50%) cases were related to patients’ family members. Eventually, no growth of Brucella was observed in 66 flasks of the BACTEC culture medium.

Considering that a definite diagnostic method is not yet accessible, a combination of methods must be applied to diagnose the disease.

 Streptococcus mutans is one of the most important microorganisms in tooth decay. Sortase A (SrtA) of S. mutans is responsible for the attachment of bacteria to the host cell and biofilm formation. Therefore, it seems necessary to investigate the inhibitors of this enzyme to prevent dental caries. Chalcones are always of interest in the medical community due to their wide range of biological activities. Many studies have reported that chalcone can help prevent caries. The present study was conducted to identify potential SrtA inhibitors with the chalcone skeleton.

 The chalcone derivatives were obtained from the ZINC15, LEA3D, and PubChem databases, and then the selected compounds were optimized by HyperChem software. The affinity of these compounds to SrtA and total binding free energy (ΔGbind) were estimated by the AutoDock 4.0 program. Finally, drug-likeness screening and absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of the best ligands were obtained using online servers.

 Compared to chalcone, four of the studied ligands, including compounds 2, 7, 8, and 9 demonstrated high affinity for binding to S. mutans SrtA, with suitable drug-likeness and ADMET properties. Ligand 9 interacted with the key residues in the active site by the most negative ΔGbind (-4.64 kcal/mol). The best conformation of this ligand had the most overlap with the chalcone.

 By complementary both in vitro and in vivo studies on the inhibitory effects of compounds 2, 7, 8, and 9, the present study can be useful in controlling tooth decay and dental diseases.

 Being infected with COVID-19 is a multifaceted syndrome that should be managed in the context of concurrent comorbidities. This study aimed to decipher the influence of cardiovascular diseases (CVDs) in the COVID-19 progression and its outcome.

 From a cohort of 184 consecutive CVD patients diagnosed with COVID-19, 86 and 98 cases were placed in the non-severe and severe groups. The clinical, laboratory, and outcome data were compared between two divisions. A logistic regression model was further applied to determine parameters associated with disease severity and outcomes.

 Patients in the severe group had significantly a higher mean age and body mass index (BMI). Of laboratory parameters, neutrophil/lymphocyte (N/L) ratio, blood urea nitrogen, serum creatinine, troponin I, and creatine kinase-myocardial band increased significantly in the severe group. Heart failure (HF) was the only CVD type that was associated with disease severity and outcome. The overall mortality rate among CVD patients was 24.5%, and patients with age over 75, dyspnea, and lower O2 saturation at the admission time were at risk of an increased chance of death.

 The mortality rate of COVID patients with underlying CVDs is high, and identifying the factors associated with disease progression is of great value. Obesity and advanced age put cardiovascular patients at the stake of severe disease and poorer outcomes. Dyspnea and hypoxia at the admission time, as well as the N/L ratio, were associated with disease severity and outcome, and chances are that they can be used as suitable predictors for recognizing those who need intensive management care.

Cystic echinococcosis (CE), caused by Echinococcus granulosus sensu lato, is a common zoonotic disease in Iran. Identifying various risk factors of this disease can pave the way for launching control and prevention programs, as well as special health education for target populations. For this purpose, this retrospective study investigated the demographic characteristics and risk factors of human hydatidosis in Hamedan.

The registered demographic characteristics of 98 patients, the risk factors of echinococcosis transmission, and the involved organs were analyzed through the profile form of patients who underwent CE surgery in two main hospitals of Hamedan province during 2014-2018. Data were analyzed using the chi-square test (or Fisher’s exact test), independent t-test, and one-way analysis of variance with Stata 16 software at a significance level of α≥0.05.

Forty-eight (48.97%) and 50 (51.02%) cases of the 98 registered CE surgeries were females and males, respectively. The age range of the patients was 8-91 years, with the significantly highest rate in 21-30 years old (23.46%, P<0.05). In addition, 77.78% of urban residents reported contact with contaminated vegetables vs. 58.49% of infected rural reported contact with contaminated vegetables and/ or dogs (P<0.05). The prevalence of infection merely in the liver (60.20%) was significantly higher than in the other organs (P<0.05).

According to the results, it seems that the targeted health education should be focused on people in their third decade of life and younger. Further, the education of urban residents should be focused more on the health of vegetables and villagers based on the simultaneous explanation of the dangers of contaminated vegetables and dogs.

 Cryptococcal meningoencephalitis is a life-threatening fungal infection in human immunodeficiency virus (HIV)-infected patients. Cryptococcus neoformans var. grubii and neoformans are the causative agents that usually respond well to fluconazole and amphotericin B. However, resistance/ non-responding cryptococcal meningitis cases to fluconazole and amphotericin B have been reported globally.

 The causative Cryptococcus was identified by phenotypic and singleplex polymerase chain reaction (PCR) targeting the putative sugar transporter (STR1) gene. In addition, the phospholipase and proteinase enzymatic activities of the isolates were determined by the plate method using egg yolk agar and bovine serum albumin agar plates, respectively. Finally, the in-vitro minimal inhibitory concentration (MIC) of fluconazole, voriconazole, and amphotericin B against isolated C. neoformans strains was determined by the broth microdilution method.

 A total of 50 C. neoformans strains were isolated from the cerebrospinal fluid of HIV-infected patients, which were further identified as variety grubii by simplex polymerase chain reaction (PCR). All the isolated strains producing phospholipase and proteinase enzymes were determined by the calculation of Pz, a ratio of colony diameter and diameter of colony plus the precipitation zone. A comparative high proteinase enzyme activity was observed, and these strains produced medium to high phospholipase (mean Pz 0.3720±0.082, range 0.23-0.56) and proteinase activity (Mean Pz 0.3069±0.086, range 0.012- 0.54). A varied antifungal MIC was detected, and voriconazole had the lowest MIC50 and MIC90 (0.03 & 0.06 µg/mL) in comparison to fluconazole and amphotericin B.

 Cryptococcus neoformans var. grubii is the commonest cause of cryptococcal meningoencephalitis in HIV-infected patients. The isolates had varied extracellular hydrolytic enzyme activities. The emergence of C. neoformans strains with higher fluconazole MIC (≥4 mcg/mL) could have resulted in treatment failure.

 Cystic echinococcosis (CE), caused by the larval stage of the Echinococcus granulosus, is a zoonotic disease and has a global distribution. Today, herbal compounds are highly regarded in order to inactivate hydatid cyst protoscoleces. This study aimed to compare the scolicidal activity of hydroalcoholic extract of Pulicaria gnaphalodes and Alhagi maurorum against hydatid cyst protoscoleces in vitro.

 The scolicidal activity of P. gnaphalodes and A. maurorum extracts were evaluated at 50, 100, 150, and 200 mg/mL concentrations following 15, 30, and 60 minutes of exposure. Then, they were compared with Albendazole (5 g/100 mL) as positive control and distilled water as negative one in similar doses. The viability of protoscoleces was confirmed with a 0.1% eosin stain test under a light microscope. The experiments were performed twice, and data were analyzed by GraphPad software version 5.0.

 The results of this study indicated that P. gnaphalodes extract killed 100% of the protoscoleces at a concentration of 200 mg/mL after 30 minutes of exposure, but the hydroalcoholic extract of A. maurorum at the same concentration and time could kill 90% of protoscoleces.

 The findings of the present study confirmed that P. gnaphalodes had a strong scolicidal effect; however; in vivo studies are needed to evaluate the effectiveness of P. gnaphalodes plant.